Method and apparatus for transmitting written characters



H. PEIN July 30, 1929.

METHOD AND APPARATUS FOR TRANSMITTING WRITTEN CHARACTERS Original. FiledSept. 29. 1925 Patented July 30, 1929.

HEINZ IPEIN, OF BREMEN, QEBMANY.

METHOD AND APPARATUS FOR TRANSMITTING WRITTEN CHARACTERS.

Original application filed September 29, 1925, Serial No.

Divided and this application filed November This invention relates to amethod and an apparatus for transmitting written characters of thatclass in which control-members are used in the transmitter for produc- 5ing fluctuations of electric energy in accordance with the path ofcurves which are obtained from the resolving of the curvelines ofwritten characters into their components, whereas in the receiver thecharacters from which the said component curves are obtained arerecomposed by the transmitted fluctuations of electric energy, as I moreparticularly described in my Patent N 0. 1,715,781, June 4, 1929 (SerialNo. 59,410, tile-d September 29th, 1925).

The object of my present invention is to facilitate the provision of thecontrol members'by multiplying them photographi(rally. Another object ofthe invention consists 2 in that the current fluctuations are not onlyaccommodated to the shape of the curves, but also that certainfrequencies can be impressed upon them so as to render it possi ble tosuperpose several frequencies upon a main wave.

According to my invention meansfor producing fluctuations of light, forinstance light-filtering bands, are used as controlmembers, whichfluctuations of light are in accordance with the path of the componentcurves. The fluctuations of light influence the resistance of cellssensitive to light, which are inserted in the transmitting circuits sothat fluctuations of electric energy according to the component curvesare effective in the transmitting device.

The invention is illustrated diagrammatically and by way of example inthe accompanying drawings.

ig. 1 is a perspective illustration of a .device for the photoelectrictransmission of the curves of written characters,- Figure 2 shows' amodification of the ray guiding parts of Fig. 1 for the simultaneoustransmission of two curves of written characters and a receivingapparatus for reeomposing the transmitted character;rFig. 3 shows acomponent-curve obtained from the decomposition of a written character;Figures 4, 5 and 6 show three forms on an enlarged scale of thelight-filtering band used in the apparatus; Fig. 7 shows a portion ofthe light-filtering band of Fig. 6 on an enlarged 7 scale; and Figures 8and 9 illustrate dia- 55 grammatically an arrangement wherein a 59,410,and in Germany February 16, 1925.

18, 1927. Serial No. 234,250.

plurality of frequencies can be superpositioned upon the wavetransmitted, and whereby the respective frequencies can be caused to actupon the writing member of the receiving station by means of resonators.

Referring now to Figs. 1 and 2, a source of light 88 is provided for thephotographic transmission of the coordinate curves; the light passing inparallel rays through a lens 89 and being directed on a light-screen 90provided with a slot 91 so that only a strip 92 of the light pencil canpass through that slot. The strip of light falls upon a band or tape 93provided with perforations 94:; the distance between the individualperforations and the edge of the band corresponding always to a distinctcharacter, in consequence whercof the perforations pertaining to equalcharacters lie vertically one below the other. Vhen the strip of lightfalls upon a perforation 94, a ray of light 95 is thereby separated fromthat strip and falls upon a certain portion of the circumference of thecylinder 96.

It is advisable to provide a system of lenses (not shown) between theperforated band 93 and the cylinder 96 in order to so modulate the rayof light that it falls upon the cylinder with a great intensity, butonly in a narrow breadth. The cylinder may consist of a transparentmaterial, as glass or the like. Upon its surface lightfiltering strips97, 97, 97" are provided each of which is equivalent to a componentcurve of a character; each band is allotted 90 to an individualperforation and'is more or less transparent in correspondence with acomponent curve of the respective character its perforation represents.

Owing to this provision, the ray of light 95 penetrates with a greateror lesser intensity into the interior of the cylinder 96 where there isprovided a parabolic mirror 96 that reflects, by reason of-its shape,all rays falling upon it to the cell 87 which is 100 sensitive to lightand is more or less excited by the various rays. As the cell 87, forinstance a selenium cell, responds to the intensity of the rays fallingupon it, the currentfluctuations necessary to transmit the Writ- 105 tencharacters according to this invention are produced.

The cylinder 96 is rotated by appropriate means, for instance, a worm 80and a wormwheel 81, so that the entering ray of light 110 wheel 102 isturned. The chain wheel is connected to and rotates a drum over whichthe band 93 passes. Thus the perforated band is moved only during thatperiod of time between the illumination of two lightfiltering bands, butis stationary when the illumination takes place.

In order to provide for a shockless transition of the rays of light froma lightfiltering band 97 to another light filtering band 97 the cylinderis, preferably, rendered transparent in a degree corresponding I to themean transparency to light of the light-filtering bands at thoseportions which are not covered by each band. For transmitting the twocomponent curves (abcissaand ordinate-curve) of a written character twodevices of the kind shown in Fig. 1 are necessary.

Referring now to Fig. 2, this figure shows the use of a source of lightfor the simultaneous illumination of two cells 87" and To attain this,the light screen 90 is provided with two slots 91 and 91*" so thattwoseparate strips of light 92 and 92* fall upon the perforated band 93shown in cross-section in Fig. 2. This band is provided with twocorresponding rows of perforations sifting out the rays of light 95 and95*" which then pass through light-filtering bands similar to the bands97, 97 (Fig. 1) into the interior of the cylinder 96, where there areprovided mirrors 97 and 97 at the two sides of a partition wall 103.These mirrors reflect the rays of light to the cells 87 and 87" whichare sensitive to light, as described.

With this constructional form there are always two cells influenced bytwo corresponding rows of perforation of a band, whereby the two curvesrequisite to produce a written character are transmitted synchronously.

Instead of sifting out two rays of light by two correspondingperforations of the perforated band, only one ray may be sifted out byone perforation, divided into two rays by reflection or an equivalentprocedure and each ray is projected onto filtering bands representingthe component curves of a character; these two filtered rays being thenused in the manner above described.

According to the varying resistance of the cells 87 and 87*" currentfluctuations are produced, which by the circuits 1 and 2 are carried tothe receiving apparatus. In the receiver magnet coils67, 67 are insertedin the circuits 1, 2, which coils act upon an armature 68 supporting awriting member 4. If the two coils are simultaneously magnetizedaccording to the component-curves of a character, the motion of thearmature 68 is the resultant of the component-curves, so that thewriting member writes the transmitted character on the paper-tape 34,which is fed forward by any suitable feeding de vice (not shown).

The light-filtering bands shown in Fig. 1 may be produced in severalways. In Figs. 4c, 5 and 6 three diaphragms are. shown which allcorrespond to the curve a) (Fig. 3), and are more or less permeable tolight according to this curve. The varying per meability or transparencyto light of the constructional form shown in Fig. 4 and dcnoted by thenumeral 97oz is attained by the larger or smaller width of a slot 104which is being moved along in front of the ray of light like adiaphragm. But the varying permeability or transparency can be broughtabout by the judicious toning of the bands in conformity with the curves(such as m, Fig. 3).

In Fig. 5 97,8 denotes a band of this kind. The third constructionalform illustrated in Figs. 6 and 7 is characterized by the feature thatintervals 106 are provided between the dark stripes 105 which are ofdifferent breadth; the mean distances y (Fig. 7) are, however, allalike, so that there are between the dark stripes 105 transparentintervals 106 the breadth of which is in accordance to thecomponent-curves of a respective character. The cells 87 or (and) 87 aare excited in certain frequencies by said distance whereas thefluctuations of the current are produced by the width or breadth of theportions 105 and 106 of the band. The intervals of frequency 106 (Fig.7) can be produced, of course, also by equally distributed andcompletely non-transparent stripes upon the bands 97a and 97B.

The invention may be used for the remote transmission of writtencharacters either by means of conducting wires or by wireless. Thewireless transmission may be eifected by means of any of knowntransmitting and receiving apparatus for wireless-telegraphy.

A particularly advantageous method in the transmission of the componentcurves by wireless consists in superimposing on a carrier wave twodiflerent oscillations of a definite low periodicity, of which theintensity of one is varied according to the path of the abscissa curveand the intensity of the other is varied according to the path of theordinate curve. At the receiving station the oscillations forming theabscissa and the or- I transmitted by an aerial 135 dinate curves whichhave been superimposed on the carrier wave are again separated out bymeans of known resonators and caused to act on a writing member in sucha manner that it writes the desired written signal as the resultant ofthe abscissa and ordinate curves. Particularly suitable for theproduction of the said oscillations to be superimposed on a carrier waveis the device illustrated in Figs. 1) and 6, 7 in which the intensitydepends on the width of the intervals 106 and the periodicity depends onthe number of intervals struck per second by the light ray 95, 95 95.

In Figs. 8 and 9 there is illustrated diagrammatically a device by meansof which two oscillations, which in intensity correspond with the courseof the COI11- ponent curves, are simultaneously superimposed on acarrier wave and are again separated at the receiving station.

Fig. 8 shows a diagram for a wireless valve or tube transmitter in whichtwo different oscillations of low frequency, for example of 500 and 700periods, are superimposed on a carrier wave of 100000 periods. Thediagram of the transmitter-consists of valve 134 of which the coupledaerial circuit 135 is energized for undamped oscillations by means of aback coupling coil 135" in the grid circuit 135 On the grid circuit 135there are superin'iposed by means of a low frequency transformer, ofwhich the secondary winding 135 is included in the grid circuit, the lowfrequency (sound frequency) oscillations. In order to impress on thegrid circuit through the same secondary winding simultaneously a numberof oscillations of low periodicity, the primary winding is divided intotwo separate windings 135 and 135 Toeach separate winding are suppliedoscillations of definite frequency, for example of 500 and 700 periods,which are then supplied to thegrid 134: through the winding 135. Thewaves are and received by the receiving aerial 136 of the receivingstation shown diagrammatically in Fig. 9. The aerial circuit is tuned tothe carrier wave to be received on which the low frequency oscillationsare superimposed. The valve 137, arranged as audion, connected theretorectifies the carrier wave so that the superimposed oscillations oflowfrequency are received in the anode circuit separate from the carrierwave but still intermingled. In order to separate the differentfrequencies from one another there are provided two resonance or siftingcircuits 138, 138 which are tuned to the desired oscillations of lowperiodicity (500 and 700 periods). The separate oscillations effect, inaccordance with their intensity the setting down of the desired letterby means of the electromagnets 67, 67, the rods 3, 3 and the pencil 4.

Finally 139 indicates a filament resistance for the valve.

The particular advantage which is ob tained by the superimposing of theoscillations corresponding with component curves on a carrier waveexists in the considerable simplification of theapparatus, in that forthe simultaneous transmission of the two component curves only onetransmitting and receiving device is necessary; and further in that thesynchronous operation of the Writing member is effected with certainty.

I claim:

1. An electric device for transmitting written characters comprising atransmitter having cells sensitive to light, circuits in which the saidcells are included, a source of light the rays of which affect the saidcells, means adapted to produce fluctuations of light in conformity withcomponent curves obtained by the decomposition of a particularcharacter, the device including a receiver means adapted to be moved bythe transmitted fluctuations of electric energy, and IOCUXDPOSO thetransmitted character, and a writing member supported by the said means.

2. An electric device for transmitting written charaeters, comprising atransmitter including cells sensitive to light, circuits in which thesaid cells are included, a source of light, light filtering meansbetween the source of light and the said cells which varies inconformity with component curves obtained by the decomposition of aparticular character, means for moving the light filtering means, meansbetween the source of light and the light-filtering means to transmitthe light-rays so that they fall only upon that light filtering meanswhich pertains to one certain character, the device including a receivermeans adapted to be moved by the transmitted fluctuations of electricenerg and to recompose the transmitted character, and a writing membersupported by said means.

3. An electric device for transmitting written characters, comprising, atransmitter including cells sensitive to light, circuits in which thecells are included, a source of light, a light filter between the sourceof light and said cells, the perviousness of which to light varies inconformity with component curves obtained by the decomposition of a.particular character, means for moving the light filter, means totransmit the light-rays so that the rays fall only upon the light filterwhich pertains to one certain character said device including a receivermeans to be moved by the transmitted fluctuations of electric energy andto recompose the transmitted character, and a writing member supportedby said means.

4. An electric device for transmitting written characters, comprising, atransmitter,

including cells sensitive to light, circuits in which the said cells areincluded, a source of light, a hollow rotary body, light-filtering meanssupported thereby for controlling the passage of the rays of light, theperviousness to light of the light filtering means varying in conformitywith component curves ob tained by the decomposition of a particularcharacter, means for rotating the said rotary body, means between thesource of light and the light-filtering means to transmit the light-raysso that the rays fall only upon that light-filtering means whichpertains to the one certain character, said device including a receivermeans movable by the transmitted fluctuations of electric energy torecompose the transmitted character, and a writing member supported bysaid means.

5. An electric device for transmitting written characters, comprising atrans mitter, including cells sensitive to light, circuits in which thecells are included a source of light, light filtering means between thesource of light and the said cells the perviousness of which to lightvaries in conformity with component curves of a certain character, meanswhereby certain frequencies are produced by the rays caused to fall uponthe said cells sensitive to light, means for moving the light-filteringmeans, means between the source of light and the light filtering meansto transmit the light rays so that they fall upon that light-filteringmeans, only which pertains to one certain character, said deviceincluding a receiver means adapted to be moved by the transmittedfluctuations of electric energy and to recompose the transmittedcharacter, and a writing member supported by said means.

6. An electric device for transmitting written characters, comprising, atransmitter, including cells sensitive to light, circuits in which thesaid cells are included, a source of light, light filtering means ascontrol members between the source of light and the said cells, theperviousness of which to light is in conformity with component curvesobtained by the decomposition of the selected char acter, means formoving the light-filtering means, a light screen between the source oflight and the light-filtering means, a slot in the said screen, a stripbetween the said light screen and the light-filter means, perforationsin the said strip which correspond to the light-filter means, wherebythe rays fall upon that light-filtering means only which pertains to onecertain character, means to intermittently move the perforated strip inaccordance with the movement of the light filtering means; said deviceincluding a receiver means movable by the transmitted fluctuations ofelectric energy to recompose the transmitted character, and a writingmember supported by said means.

7. A method for transmitting written characters which consistsindecomposing the curve-lines of the character into its component-curves,producing fluctuations of electric energy in accordance with the path ofthe component-curves, imparting fre quencies to the fluctuations ofelectric energy, superimposing the frequencies which in intensitycorrespond with the component curves of a written character on a commoncarrier-wave, and separating the said frequencies at a receiving stationby means of resonators and causing them to act on and correspondinglyinfluence a writing member.

In testimony. whereof I afiix my signature.

HEINZ PEIN.

